(1) Field of the Invention
This invention relates to a stocker apparatus and a substrate treating apparatus for storing substrates such as semiconductor wafers, glass substrates for photo resist, glass substrates for liquid crystal displays, or substrates for optical disks (hereinafter called simply “substrates”).
(2) Description of the Related Art
A conventional substrate treating apparatus of the single substrate type, as shown in FIG. 1, includes an indexer mechanism 100, four openers 101a-101d and treating units (not shown). The openers 101a, 101b, 101c, . . . , when not distinguished, will be referred to as “opener(s) 101”.
Each opener 101 receives, on a support table, a FOUP (Front Opening Unified Pod) F which is a container storing a plurality of substrates in multiple stages in a substantially horizontal state, and opens and closes a lid of the FOUP F. When the lid of the FOUP F is opened by the opener 101, the indexer mechanism 100 transports the substrates from the FOUP F to treating units.
In recent years, the substrate treating apparatus has been constructed to include an increased number of treating units which are stacked in multiple layers, to improve throughput of the substrate treating apparatus. The number of openers 101 installed has also been increased correspondingly. However, as shown in FIG. 2, the openers 101 simply juxtaposed in one row will increase the width of the substrate treating apparatus in the direction of X-axis in which the openers 101 are juxtaposed. This enlarges an installation area of the substrate treating apparatus.
Then, the following technique has been proposed (e.g. in Japanese Unexamined Patent Publication No. 2000-124301).
This substrate treating apparatus includes a cassette table for receiving carrier cassettes each storing a plurality of substrates, and an auxiliary arm for loading and unloading the substrates into/from the carrier cassettes. Between the cassette table and auxiliary arm, a container is provided for storing the carrier cassettes in two, upper and lower stages. This container is movable up and down.
A carrier cassette placed on the cassette table is first transported to one of the two stages of the container. The auxiliary arm takes the substrates out of the carrier cassette transported into the container. When all the substrates have been taken out, the carrier cassette now empty is displaced by vertical movement of the container.
By vertical movement of the container, a next carrier cassette placed on the cassette table and storing substrates to be treated can be transported to the other stage of the container. Subsequently, the auxiliary arm can take the substrates out of the carrier cassette transported to the other stage of the container.
Such construction including the container and cassette table can store (keep) two carrier cassettes in the container. Where, for example, four of this construction are juxtaposed, a maximum of eight carrier cassettes can be stored. Therefore, enlargement of the apparatus can be inhibited while being capable of receiving an increased number of carrier cassettes.
A FOUP station (stocker apparatus) has been disclosed as an apparatus similar to the above and capable of receiving many FOUPs (e.g. Japanese Unexamined Patent Publication No. 2005-150495).
In this apparatus, a mechanism for transporting FOUPs F can feed many substrates to a substrate treating apparatus by transporting a FOUP F made empty of substrates to a different location, and transporting another FOUP F storing substrates to be treated to a transfer position to feed the substrates from this FOUP F.
The conventional apparatus with such a construction has the following drawback.
The substrates having received a predetermined treatment cannot be collected unless the mechanism for transporting FOUPs F puts an empty FOUP F on standby on an opener beforehand for substrate collection. When, for example, a delay occurs in transporting the empty FOUP for use in collecting substrates, a resulting standby time will impair efficient collection. A smooth operation is difficult without rules determined beforehand for transporting empty FOUPs F and collecting treated substrates.